1. Field of the Invention
This invention relates to a device for clearance-free mounting of a pane of glass onto a rigid support.
It applies notably, though not exclusively, to the mounting of a protective pane of glass onto flat cathode or liquid crystal screens.
2. Description of the Prior Art
The achieve this result, the prior art has used rectangular bracket-shaped clamps of which one of the two legs is applied against the upper side of the pane of glass, while the other is drilled with a hole in which is inserted a screw enabling the clamp to be fastened to the pane support.
The utilisation of such clamps, always of the same dimensions, imposes that the panes of glass be of perfectly calibrated thickness obtained by precise and therefore costly machining.
If one wishes to avoid limiting oneself to the use of panes of glass of constant thickness to obtain clearance-free mounting, these thickness variations must be compensated either by clamps of adapted shapes, or by shims of variable thicknesses, which is ill-suited to the mounting of panes of glass in an industrial process with high production rates.
In addition, during tightening of the fastening screw, the clamp exerts a pressure directed perpendicularly to the upper side of the pane of glass. If this pressure exceeds a certain threshold, the glass breaks. This device therefore requires the use of a dynamometric screwdriver indicating the tightening pressure.
Moreover, due to the prestressing exerted by the clamps, the pane of glass is made fragile and therefore risks being broken by the effects of external action such as e.g. differential expansion phenomena.
In this respect, it should be recalled that glass has a high coefficient of expansion.